Wednesday, September 16, 2009

There are so many words which are available to express the idea of balance between things in nature and life. There are also many practical considerations, like if you want to use a swing in a playground, the other person on the far end of the swing must balance your weight if you want to use the swing enjoyably. If you are on a lake with a canoe on a camping trip, you take care loading the canoe so it sits in the water evenly from stem to stern if you want the canoe to be easy to paddle and control. If you have a truck you are careful loading the cargo area so the front part of load is a bit heavier than the rear so weight is not taken off the front wheels of the truck making it steer poorly. On and on, balance is an essential part of ideal functioning.

The same is true about computer LCD displays and printing. The display brightness must match the brightness of paper white if an image adjusted on-scren can be expected to print with the correct density. The one thing I did not mention regarding the “prints too dark” problem before is why digital photographers calibrate and profile their display, so the colors they see on screen can be matched in the colors reproduced with a print of the image on-screen. Here again a matched balance between display and print brightness is crucial.

Many, many photographers with computers get a sensor, colorimeter and software to calibrate and profile their display. Some of the software packages suggest putting the display at the factory default setting to begin the process, others offer different suggested white luminance target setting of 120.0 or 140.0 CD/m2 as the target display brightness goal. The white luminance equivalent of printing paper white is between 80.0 and 90.0 CD/m2, so these suggested display brightness goals will not provide a match for printing in either density or color. When a color profile is made at a high brightness and then used to make a print that is at a lower brightness, how can the color match - it can’t, not as it would for balanced brightness between display and paper.

But even more if you calibrate and profile a display for a brighter level than paper, the color balance will not be correct for printing. The brighter the display the further out of balance the color matching will be. In other words most of the Color Management products sold for calibrating and profiling displays cannot provide either precise color matching or a good brightness match between display image and a print made by a color managed work flow from that image. In other words, the bottom line is that to some extent if you are calibrating and profiling a display, the display brightness must match paper white if print matching in either color or print density is to be expected.

How this obvious need for balance between display and printer paper was ignored by almost everyone is hard to imagine. Maybe because the native brightness of CRT monitors and paper white just coincidentally matched did not cause anyone to think about it. And when LCD displays arrived, being able to make them brighter and easier to see in brightly lit rooms was more important to selling displays than the consequence of being out of balance with printing.If you have a comment, they are welcome, so please post it. If you have a question you want me to answer please address an e-mail to David B. Brooks at: goofotografx@gmail.com